Space Elevator Extrusion Construction Method

ABSTRACT

A method of constructing an elevator core structure for a space elevator tower. The actively stabilized space elevator tower is a pneumatically pressurized structure formed from flexible sheet material. This construction method comprises extruding core segments from a liquid core material. Pods containing control and stabilization machinery are embedded in the core segments as they are extruded, and raised. Fiber can be embedded in the elevator core structure to increase elasticity. There are also options to provide the control and stabilization machinery on a base, and to raise the pods with a roller system and pneumatics. The freestanding tower can be used for launch activities, tourism, observation, energy generation, scientific research, and communications.

FIELD

This invention relates to space elevators, and more particularly to a method of constructing a freestanding space elevator tower.

BACKGROUND

In order to access space or near space, payloads must gain significant potential and kinetic energy. Traditionally, regions above 50 km in altitude can only be accessed using rocketry, where mass is expelled at high velocity in order to achieve thrust in the opposite direction. This process is extremely inefficient as rockets must counter the gravitational force during the flight by carrying mass in the form of propellant and must overcome atmospheric drag. In contrast, if a payload is hauled to space or near space along an elevator system, the work done is significantly less as no expulsion mass must be carried to do work against gravity, and lower ascent speeds in the lower atmosphere can virtually eliminate atmospheric drag. Elevator cars' motion may also be powered remotely by electrical or inductive means, eliminating the need to carry any fuel.

It has previously been proposed, most famously by Arthur C. Clarke in his 1978 novel, The Fountains of Paradise, that a space elevator could be constructed using a cable and counter-balanced mass system. For Earth's gravity and spin rate, such a solution requires a cable of at least 35,000 km in length and a counter balance mass similar to a small asteroid. Such a system could be constructed by launching the cable into space or manufacturing it in situ and lowering it into contact with Earth. However, the technological obstacles that must be overcome, including the construction of a cable with suitable strength characteristics or the in-space construction of the apparatus, have not been realized since the concept was popularized by Clarke. Known materials are simply not strong enough to enable the construction of a cable of that length that would even be capable of supporting its own weight.

SUMMARY

The present invention is a method of constructing a space elevator tower. The actively stabilized space elevator tower has a segmented elevator core structure, each segment being formed of at least one pneumatically pressurized cell. The method of constructing the tower comprises extruding core segments from a liquid core material. As the core segments are extruded, they are embedded with pods containing control and stabilization machinery, and raised. The method includes a means of increasing the elastic resistance of the structure by embedding fibers into the elevator core structure. There is also an option to provide the control and stabilization machinery on a base, extruding the core segments around the base and, as required, mounting the control and stabilization machinery as each core segment is extruded.

The space tower can be used for the delivery of payloads to at least one platform or pod above the planetary surface for the purposes of space launch or for the recovery of a rocket stage. The space elevator tower may also be used to deliver equipment, personnel and other objects or people to at least one platform or pod above the surface of the Earth. While the described space elevator tower can provide access to lower altitude regions, the space elevator tower can also be scaled to access altitudes above, for example, 15 km, the typical ceiling altitude for commercial aviation. The space elevator tower can be further scaled to provide direct access to altitudes above 200 km and with the gravitation potential of Low Earth Orbit (LEO).

Although ascending to an altitude significantly below 35,000 km will not place a payload in Earth orbit, a platform or pod supported by the space elevator tower has significant advantages over a surface-based launch platform. While surface-based rockets must be designed to overcome atmospheric air resistance, launch from a high-altitude platform has no such requirement, and, consequently, existing space equipment such as an orbital transfer stage or conventional upper stage can be used to insert payloads directly into Earth orbit. Ideally, payloads should be raised to the highest feasible altitude before launching in order to maximize the energy advantages; however, the energy advantages for space flight are readily leveraged above 5 km.

A platform or pod supported by the space elevator tower also has significant advantages over orbiting satellite platforms. Geographically fixed, but providing access to regions of space closer to the surface than geostationary orbit, elevator platforms provide the ideal means to communicate over a wide area and to conduct remote sensing and tourism activities. As a tourist destination, the elevator platforms provide stations located at fixed attitudes from the surface for observation. The elevator platforms provide the means to safely access a region of space with a view extending hundreds of kilometers.

The space elevator tower may also provide a near-surface observation platform with oversight over a fixed geographical area. Such platforms can be used for observation, remote sensing and communications. Small systems may be mobile and delivered to sites for temporary applications for example to provide temporary communications towers typically between 25 m and 150 m. The space elevator tower may also provide a platform for energy generation. Used with an elevator component equipment may be accessed and maintained during operation. Used without an elevator component, equipment may be installed only during the construction of the apparatus.

The invention provides a method of constructing the freestanding space elevator tower. The method comprises the extrusion of core segments from a liquid core material. The core segments are embedded with embedding pods containing control and stabilization machinery, and raised. Fiber can be embedded in the elevator core structure to increase elasticity. There are also options to provide the control and stabilization machinery on a base, and to raise the pods with a roller system and pneumatics.

Further aspects and advantages of the invention will appear from the following descriptions taken together with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an isometric view showing a method of constructing an elevator core structure.

DETAILED DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a method of constructing the space elevator tower 10. It is to be appreciated that the construction method is not limited to the following example, and that features of the following configuration may be combined to produce further variations of the construction method without departing from the scope of the present invention.

In the method shown in FIG. 1, the elevator core structure 12 is erected vertically using a mechanism that extrudes core segments 14. Pods 24 containing control and stabilization machinery are embedded in the elevator core structure 12 as it is extruded by a roller system 995 from a stack of similar pods 24. Gas and power conduits 964 are lifted with each pod 24. The core segment walls and pressure compartments are formed as an extrusion molding of a liquid core material 996. Optionally, a winding mechanism 998 embeds fibers into the elevator core structure 12 in order to increase the elastic resistance of the structure. Pneumatic pressure and a roller mechanism may be used to raise and lower core sections. 

1. A method of constructing an elevator core structure for a space elevator tower, the method comprising: a) extruding core segments from a liquid core material; b) embedding pods containing control and stabilization machinery in the core segments as they are extruded; and, c) raising the pods
 2. The method of claim 1, further comprising embedding fibers into the elevator core structure in order to increase the elastic resistance of the structure.
 3. The method as claimed in claim 1 or 2, including providing the control and stabilization machinery on a base, extruding the core segments around the base and, as required, mounting the control and stabilization machinery as each core segment is extruded.
 4. The method as claimed in claim 1 or 2, including raising the pods with a roller system and pneumatics. 